The present invention relates to a method of fabricating gate dielectric for use in semiconductor device, and more particularly, to a method of fabricating gate dielectric for use in semiconductor device having a high dielectric constant via nitridation.
Thin ZrO2 film, a film that has been spotlighted as a gate dielectric with high dielectric constant for next generation, is reported to enable to have excellent electrical properties via various processing optimizations. However, as is the case with other metal oxides, it becomes inevitable to perform heat treatment for thin film of ZrO2 at a relatively high temperature when using the thin ZrO2 film as a dielectric gate for MOSFET, and this results in the drastic increase in effective thickness due to the growth(increase) in interfacial layer of silicate or silicon oxide which is formed in the interface between silicon substrate and thin film of ZrO2.
The present invention relates to a method of fabricating gate dielectric for use in semiconductor device having a high dielectric constant comprising formation of a metal oxide on a silicon substrate, nitridation to incorporate nitrogen component to said metal oxide and reoxidation of said metal oxide that contains said nitrogen component. Examples of said metal oxides include ZrO2, HfO2, La2O3, Al2O3 and Ta2O5, and other metal silicates such as ZrSixOy, HfSixOy, LaSixOy, AlSixOy and TaSixOy can be also used for the same purpose. Further, the nitridation can be performed by heat-treating the resulting product, wherein said metal oxide is formed within, in a nitrogen-containing gas atmosphere; performed by plasma treatment by exposing said metal oxide to a nitrogen-containing plasma atmosphere; or performed by ion implantation of nitrogen component to said metal oxide.
Therefore, the object of the present invention is to provide a gate dielectric for use in semiconductor device which is able to remarkably inhibit the increase effective thickness resulted from a post heat-treatment at high temperature by performing steps of forming a film of metal oxide such as ZrO2 followed by nitridation and reoxidation.